1. Field of the Invention
The present invention relates to a location registration control method for registering the location of a communication terminal served by a mobile communication network, as well as to a mobile communication network and a communication terminal using the method.
2. Description of the Related Art
In a mobile communication system which comprises a mobile communication network including base stations, switches, and other facilities, and mobile stations such as cellular phones in the mobile communication network, a communication service area is composed of a plurality of location areas. To be able to issue an incoming call request to any mobile station, the mobile communication network of such a mobile communication system must track each mobile station; i.e., must determine the location area where each mobile station is located within the communication service area. Therefore, the mobile communication network performs so called location registration processing for registering, in response to a location registration request from each mobile station, identification information of a location area in which the mobile station is present.
To effect location registration processing, each mobile station transmits a location registration request signal to the mobile communication network when, for example, the mobile station detects a change in its position to another location area.
In a conventional mobile communication system, sections of location areas i.e., boundaries between location areas within a communication service area are fixed. In other words, location areas comprise fixed sections. Therefore, a mobile station which is operated in a transportation means moving at speed within an area which is large relative to a size of location areas must frequently transmit a location registration request signal to the mobile communication network.
By contrast, when an incoming call directed to a mobile station within a location area occurs, all switches and base stations located within the location area within which the mobile station is present issue paging signals simultaneously. That is, at the time of an incoming call, a mobile station which moves within a limited area in a location area generates the same volume of traffic as a mobile station of an owner moving widely within a location area.
As has been described, in the conventional mobile communication system, unnecessary traffic is generated for location registration and incoming calls, and this problem has not been satisfactorily solved.